64b on 3Gb RAM will be a squeeze. If not doing a lot of 3D jump into bios and lower the video allocation down a bit to get some more.. You'll probably find there is only 700MB-1.2 actually usable once the OS has at it similar to my olds PC. Makes for slow initial opening of browsers etc.

The rest of the speed loss comes from the browser caching data - more and more they try to 'enhance' your experience by caching more and more of the site locally = disk writes. Both a slow drive and less RAM will impact that. Think the push for it now is due to SSDs being just so fast.